Emulsion polymerization is a specific polymerization process in which monomers of low water solubility are emulsified in water with the help of emulsifiers and are polymerized using water-soluble initiators such as potassium peroxodisulfate or redox initiators. Anionic and/or nonionic surfactants are the essential constituents here. Via micelle formation in the aqueous solution, they ensure the process of emulsion polymerization.
In the course of emulsion polymerization processes, surfactants are often diluted with water or are introduced into an aqueous reaction solution; the surfactants are then present in the concentration required for the emulsion polymerization process. Here, the surfactants generally pass through a wide concentration range, particularly if they are present beforehand as 100% strength systems, i.e. are water-free. The operating temperature here is often in the range around 25° C. Many surfactants exhibit a miscibility gap with water as a function of the temperature and the concentration. This means that in said gap they are not soluble in water, which manifests itself in the formation of an insoluble gel block which prevents immediate further processing of the reaction mixture. This is an extremely undesired process.